Incipio OffGRID Portable Backup Battery 4000 mAh (1 port), Black Certified "Made for Amazon" OffGrid portable battery 4000 mAh (1 port) for Fire Phone Rechargeable lithium-polymer battery with 4000mAh capacity LED indicators display power status and available capacity Slim and lightweight design is ideal for portability Easily charge your offGRID Portable Backup Battery with the included Micro USB cable